(1) Field of the Invention
The present invention relates to a method and system for controlling a travelling body so as to move forward along the predetermined route of the movement of the travelling body.
(2) Description of the Prior Art
Examples of a travelling body which should be moved forward along a predetermined route of the movement of the travelling body while a given work is performed, include a shield for driving a tunnel, or for laying a water supply pipe or a sewage pipe, an unmanned vehicles, and the like.
The aforementioned shield, unmanned vehicles, and the like are generally comprised of a body and a steering means for controlling the direction of movement of the body so as to move forward along the predetermined route.
Particularly, when laying various pipes in the ground by using a shield, the shield encounters a varying intensity of resistance of the soil due to a change in the nature of soil, the presence of groundwater, etc.
Because of this, according to circumstances, even if a shield is driven by uniform power, the shield is moved in the direction of less resistance off the predetermined route. In such a case, an operator measures with the eye the quantity and direction of deviation of the shield from the predetermined route resulting from the movement of shield in the ground, and makes the needed correction in the direction of the shield by controlling the steering means according to the quantity and direction of deviation of the shield from the predetermined route.
Now, the steering means of the shield is concretely explained.
For example, the shield developed by the present applicant and described in Japanese Patent Laying-open No. 57-205698 is comprised of a tail part and a head part positioned on the front end of the tail part which are connected with each other. A graduated plate is fixedly mounted on the fixed location of the aforementioned tail part. A pointer is arranged on the head part, which pointer faces the graduated plates, and can move as the head part is deflected with respect to the tail part. An image of the aforementioned graduated plate is monitored by a TV-camera and shown on a display of a monitor TV.
Further, a visible ray having such a straight travelling property as that of laser beam, etc., as a reference ray is sent along the predetermined route (a direction of excavation or a pipe-laying direction). This visible ray is projected on the graduated plate, while an operator measures with his eye the first position of the visible ray on the graduated plate when starting the excavation, and then the operator measures with his eye the difference between the first position of the visible ray when starting the excavation and the second position of the visible ray after moving forward the shield through some length and the change in the direction of the shield, and adjusts the travelling direction of the shield by driving the jacks according to the measured difference between the first position of the visible ray when starting the excavation and the second position of the visible ray after moving forward the shield through some length.
As above-mentioned, the operation of the shield is largely dependent on the experience and perception of operator, and therefore an operator is required to have high skill. Accordingly, a shield which can be readily operated is required.